Americans are starting to believe in climate change – but for the wrong reasons

Here's a paradox. The proportion of Americans who say that global warming is under way is growing. But this is largely for the wrong reasons.

A new opinion poll by the National Survey of American Public Opinion has found that 62 per cent of Americans agree with most scientists that the climate change is taking place. That's up 7 per cent from a year ago and back to levels last seen in the autumn of 2009 before the release of the hacked "Climategate" emails, the failure of the Copenhagen summit, the discovery of errors in the latest report of the Intergovernmental Panel on Climate Change, and the cold winter that then hit much of the country. Scepticism, it shows, reached a peak in the spring of 2010, in the immediate aftermath of all those events, but has dwindled since.

Yet the main reason for the shift – which is also seen in other recent US polls – appears to have been recent weather patterns, which, whatever some sceptics and greens claim, is a different matter from longer term climate change. Two years ago, polls showed (as in Britain) that the harsh winter had been the main factor in persuading people that global warming was not taking place. Now, warmer temperatures and an increase in droughts, storms and other extreme events – four out of five Americans live in states hit by weather-related disasters since 2006 – are (equally wrongly) fuelling a growing conviction that climate change is happening after all.

Interestingly, a Pew poll in December, which also showed a sharp rise in those saying the world has been warming, suggests that this was particularly big – a full 22 percentage points since Sept 2010 – among moderate or liberal Republicans, leaving only Tea Party adherents unmoved in their faith that it is not happening. This trend – which has taken place despite the strongly expressed scepticism of almost all the party’s presidential candidates – suggests it might be a handy wedge issue for the Democrats this autumn. But don’t hold your breath: Obama shows no sign of realising it.